Solvent extraction system and process for hydrothermal liquefaction

Abstract

A method can include: in a heat exchanger, cooling a biocrude oil emulsion stream received from a biocrude oil emulsion source, wherein the emulsion can include a biocrude oil phase, an aqueous phase, and solids; in a first mixing vessel, mixing the emulsion with a solvent to dissolve the biocrude oil phase and form a biocrude-solvent solution; in a first separator assembly, separating the biocrude-solvent solution from the aqueous phase and the solids; in a solvent recovery apparatus, recovering solvent from the biocrude-solvent solution; in a second mixing vessel, mixing the solvent with the aqueous phase and the solids received from the first separator assembly to dissolve biocrude oil remaining in the aqueous phase and the solids; and supplying the solvent and biocrude oil to the first mixing vessel as the solvent. In some examples, such a method can more effectively separate biocrude oil from the emulsion than conventional techniques.

We claim: 
     
         1 . A method comprising:
 in a heat exchanger, cooling a biocrude oil emulsion stream received from a biocrude oil emulsion source, the biocrude oil emulsion stream comprising an emulsion including a biocrude oil phase, an aqueous phase, and solids;   in a first mixing vessel, mixing the emulsion with a solvent to dissolve the biocrude oil phase and form a biocrude-solvent solution;   in a first separator assembly, separating the biocrude-solvent solution from the aqueous phase and the solids;   in a solvent recovery apparatus, recovering solvent from the biocrude-solvent solution;   in a second mixing vessel, mixing the recovered solvent with the aqueous phase and the solids received from the first separator assembly to dissolve biocrude oil remaining in the aqueous phase and the solids; and   providing the recovered solvent and dissolved biocrude oil to the first mixing vessel as the solvent.   
     
     
         2 . The method of  claim 1 , wherein the biocrude oil emulsion stream is cooled in the heat exchanger to a temperature from 20° C. to 100° C. 
     
     
         3 . The method of  claim 1 , wherein the biocrude oil emulsion stream is cooled in the heat exchanger to a temperature from 40° C. to 80° C. 
     
     
         4 . The method of  claim 1 , further comprising:
 in a pump, pressurizing the emulsion before the emulsion enters the first mixing vessel.   
     
     
         5 . The method of  claim 1 , further comprising:
 in a second heat exchanger, heating aqueous phase and solids received from the second mixing vessel; and   in a water product stripper apparatus, separating solvent from aqueous phase and solids received from the second heat exchanger.   
     
     
         6 . The method of  claim 5 , further comprising:
 in the second heat exchanger, circulating aqueous phase and solids received from the water product stripper apparatus to heat the aqueous phase and the solids received from the second mixing vessel.   
     
     
         7 . The method of  claim 5 , further comprising:
 supplying solvent received from the water product stripper apparatus to the second mixing vessel as a portion of the recovered solvent provided to the first mixing vessel.   
     
     
         8 . The method of  claim 1 , further comprising:
 circulating biocrude-solvent solution received from the first separator assembly through the heat exchanger to cool the biocrude oil emulsion stream.   
     
     
         9 . The method of  claim 1 , further comprising:
 in a second separator assembly, separating the solvent and dissolved biocrude oil received from the second mixing vessel from aqueous phase and solids received from the second mixing vessel.   
     
     
         10 . A system comprising:
 a biocrude oil emulsion source;   a heat exchanger disposed downstream of the biocrude oil emulsion source, wherein the heat exchanger is configured to cool a biocrude oil emulsion stream received from the biocrude oil emulsion source, and wherein the biocrude oil emulsion stream comprises an emulsion including a biocrude oil phase, an aqueous phase, and solids;   a first mixing vessel disposed downstream of the heat exchanger, wherein the first mixing vessel is configured to mix the emulsion with a solvent to dissolve the biocrude oil phase in the emulsion and form a biocrude-solvent solution;   a first separator assembly disposed downstream of the first mixing vessel, wherein the first separator assembly is configured to separate the biocrude-solvent solution from the aqueous phase and the solids;   a solvent recovery apparatus disposed downstream of the first separator assembly, wherein the solvent recovery apparatus is configured to separate biocrude oil and solvent from the biocrude-solvent solution;   a second mixing vessel disposed downstream of the first separator assembly and disposed downstream of the solvent recovery apparatus, wherein the second mixing vessel is configured to mix solvent received from the solvent recovery apparatus with aqueous phase and solids received from the first separator assembly to dissolve biocrude oil remaining in the aqueous phase and the solids; and   a second separator assembly disposed downstream of the second mixing vessel, wherein the second separator assembly is configured to separate solvent and biocrude oil from the aqueous phase and solids received from the second mixing vessel and supply the solvent and biocrude oil to the first mixing vessel as the solvent.   
     
     
         11 . The system of  claim 10 , wherein the solvent recovery apparatus comprises a fractional distillation column. 
     
     
         12 . The system of  claim 10 , further comprising a steam source configured to heat the solvent recovery apparatus. 
     
     
         13 . The system of  claim 10 , further comprising a first condenser disposed downstream of the solvent recovery apparatus, wherein the first condenser is configured to condense solvent received from the solvent recovery apparatus. 
     
     
         14 . The system of  claim 13 , further comprising a second condenser disposed downstream of the first condenser, wherein the second condenser is configured to condense light hydrocarbons received from the first condenser. 
     
     
         15 . The system of  claim 14 , wherein the light hydrocarbons are introduced into a biocrude oil stream provided by the solvent recovery apparatus. 
     
     
         16 . The system of  claim 15 , further comprising a de-oiling cyclone disposed downstream of the second separator assembly, wherein the de-oiling cyclone is configured to separate solvent from aqueous phase and solids received from the second separator assembly. 
     
     
         17 . The system of  claim 16 , wherein the de-oiling cyclone is configured to provide the solvent to the second mixing vessel. 
     
     
         18 . The system of  claim 16 , wherein the de-oiling cyclone is configured to introduce the separated solvent into an aqueous-solids stream disposed upstream of the de-oiling cyclone and downstream of the second separator assembly. 
     
     
         19 . The system of  claim 10 , further comprising a water product stripper apparatus disposed downstream of the second separator assembly, wherein the water product stripper apparatus is configured to recover solvent from aqueous phase and solids received from the second separator assembly. 
     
     
         20 . A system comprising:
 a hydrothermal liquefaction (HTL) reactor system configured to produce an emulsion comprising biocrude oil and an aqueous phase; and   a HTL solvent extraction system disposed downstream of the HTL reactor system comprising:
 a first mixing vessel disposed downstream of the HTL reactor system, wherein the first mixing vessel is configured to mix the emulsion with a solvent; 
 a first separator assembly disposed downstream of the first mixing vessel, wherein the first separator assembly is configured to receive the emulsion mixed with the solvent and separate the biocrude oil and the solvent from the aqueous phase; 
 a solvent recovery apparatus disposed downstream of the first separator assembly, wherein the solvent recovery apparatus is configured to receive biocrude oil and solvent from the first separator assembly and separate the biocrude oil from the solvent; 
 a second mixing vessel disposed downstream of the first separator assembly and the solvent recovery apparatus, wherein the second mixing vessel is configured to mix solvent received from the solvent recovery apparatus with aqueous phase received from the first separator assembly to dissolve biocrude oil remaining in the aqueous phase; and 
 a second separator assembly disposed downstream of the second mixing vessel, wherein the second separator assembly is configured to separate solvent and biocrude oil from aqueous phase received from the second mixing vessel and supply the solvent and the biocrude oil to the first mixing vessel as the solvent.